serial: 8250: Flush DMA Rx on RLSI
authorIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tue, 8 Nov 2022 12:19:52 +0000 (14:19 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 9 Nov 2022 12:04:39 +0000 (13:04 +0100)
commit1980860e0c8299316cddaf0992dd9e1258ec9d88
tree8b06ac866386b579930ef260ef2c3229fa3bd012
parent7090abd6ad0610a144523ce4ffcb8560909bf2a8
serial: 8250: Flush DMA Rx on RLSI

Returning true from handle_rx_dma() without flushing DMA first creates
a data ordering hazard. If DMA Rx has handled any character at the
point when RLSI occurs, the non-DMA path handles any pending characters
jumping them ahead of those characters that are pending under DMA.

Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/8250/8250_port.c